Lufkin HX46 Wood Folding Rule, Red End, Brass Plated Hook, 5/8"X6'Highlights : Graduated slide rule extends up to 6" Slide rule runs under friction in T slot Stops at each end to prevents slide from falling out Has hook; zero falls at inside of hook, for distance measuring Marked both sides and both edges 16" stud centers in red, regular outside markings Boxed WARNING: This product can expose you to chemicals including Lead, which is known to the State of California to cause cancer and birth defects or other